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Using Broken Bones to Reconstruct Lives

Andrea Lessa argues in her newest paper on trauma in pre-colonial Brazilian populations that fractures can expand knowledge on the stress and lifestyles of a given population. “Fractures thus point to tendencies in the division of labour within a society, in addition to providing indirect information on individuals’ quality of life, based on inferences concerning the types and amount of activities performed (Lessa 2011:159). She argues that by taking a more cultural approach towards examining fractures, they can be used to reconstruct lifestyles and better understand the social roles of individuals. This is called a biocultural perspective: a combination of paleopathological, archaeology, and environmental evidence in order to infer social and cultural patterns.

Lessa used a number of collections of sambaqui and hunter-gather-fisher populations in Rio de Janeiro and Santa Catarina. All groups were argued to have similar resource rich environments and toolkits, leading to the argument that their activities and therefore prevalence of pathologies would be similar. The only difference between the sambaqui and hunter-gather-fisher populations was the presence of extensive shell mounds in the former, and a difference in occupation- with sambaqui occupying the region from 4000 to 1000 BCE and hunter-gather-fisher groups occupying it after 1000 BCE.

Lessa used 64 males and 55 females from sambaqui populations, and 57 males and 39 females from hunter-gather-fisher populations, for a total of 215 individuals examined.The individuals spanned age ranges from young adult (18-29), adult (30-49) and old adult (50+). She examined only acute fractures, defining these as “a discontinuity of, or a crack in, skeletal tissue, with or without injury to overlying soft tissue”. Based on analysis of the fractures by population and sex, Lessa was able to compare the two populations (see Table below).

Lessa found that there was an increase in accident based fractures in the hunter-gather-fisher population, especially in males. She argues that this may be due to a change in subsistence practices between the groups. Based on archaeological evidence, the sambaqui appeared to have focused more on seafood and fishing, whereas the hunter-gather-fisher group had a more diverse diet with mainland hunting more of a focus. The rugged coastal cliffs which separate the sites from the inland in this region may be the reason for increased injuries as people begin to rely more on inland food sources. However there is no change in risk between males and females, suggesting that either they engaged in similar tasks or that all tasks carried the same amount of risk.

Looking at the location of the fractures is important for determining possible behaviors that led to them. The highest number of fractures occurred in the arm bones and clavicles, suggesting that the individuals were trying to prevent themselves from falling. The second most common fracture were those in the leg bones, suggestive of falling from a great height and trying to absorb the fall. These fractures were only present in males of both populations- suggesting a division of labor where men were engaged in more activities like climbing trees or steep cliffs and women were engaged in gathering along the coastal cliffs where slipping was more likely than falling.

Lessa admits that the sample size does restrict interpretations, but views this as a starting point for creating more nuanced interpretations of pre-colonial populations in Brazil. Instead of just looking at the prevalence of fractures and the types, Lessa expanded on this by using these to interpret changes in subsistence and gendered division of labor. By looking at fracture patterns she was able to create a fuller interpretation of how these populations experienced life and the risks involved in their subsistence strategies. While there are problems in the interpretation, most of these are due to a lack of evidence that is fully acknowledged and will hopefully be addressed in future studies. More robust archaeological information would aid in interpretations of activities, and ethnographic studies could be potentially helpful in interpreting fracture patterns.

Taking the biocultural perspective is extremely important. While the evidence itself is pivotal, the interesting part of doing archaeological work is the interpretations from that evidence. As I have mentioned previously in my post on Bioarchaeology is Anthropology, it is important to understand the greater social and environmental context of bioarchaeological evidence in order to better interpret the past. More studies like Lessa’s need to be conducted if we are going to create more robust interpretations of the past. While these types of biocultural interpretations can be prone to story telling or ‘just so’ stories, the combination of biological, archaeological and environmental evidence is important.

Works Cited

Lessa. 2011. Daily Risks: A Biocultural Approach to Acute Trauma in Pre-colonial Coastal Populations from Brazil. In International Journal of Osteoarchaeology 21: 159–172.